1. Technical Field
The present invention relates to a data driving circuit, a display apparatus comprising the same and a control method thereof.
2. Discussion of Related Art
Generally, a liquid crystal display and an organic light emitting device include a thin-film transistor substrate to independently drive each pixel.
The thin-film transistor substrate is provided with a plurality of gate lines transmitting gate signals and a plurality of data signals transmitting data signals. The thin-film transistor substrate includes a thin-film transistors connected to the gate lines and the data lines, and a plurality of pixel electrodes connected to the thin-film transistors. The above-described display apparatus includes a gate driver turning on/turning off the thin-film transistors and a data driver applying the data signals corresponding to image signals to the date lines.
The data driver may include a digital-analog converter converting a received digital signal to an analog signal and an amplifier, which is connected to the digital-analog converter, amplifying the data signal. The amplifier has a plurality of switches formed of transistors and may have an offset, even though an input value is “0” for its inherent character. The offset may be a positive offset having a positive value or a negative offset having a negative value. To cancel these offsets, the sum of the data signal and an offset compensation value is input to the amplifier. The polarity of the offset compensation value is alternately changed on a frame by frame basis, according to a frame offset cancellation method. In the case of the frame offset cancellation method, it is very important to exactly identify the frame changes. Generally, a vertical synchronization start signal indicating a beginning of a gate signal is useful to determine the frame's change point. Recently, one or more of the vertical synchronization start signals are output for one frame according to a precharging driving method or an impulsive driving method. Thus, the data driver may have a problem identifying a frame and its start point.